/Jenkins

Learning Jenkins

Table of Contents

0. Introduction

1. Install Jenkins

  • System requirements
    • Can run with both personal computer or Server
    • Normally: Hardware: 256 MB RAM, 1 GB disk space; Software: Java 11 or higher (JDK or JRE)
    • For Container: Hardware: 1 GB RAM, 10 GB disk space; Software: Docker Personal Edition, Java is not required
  • Install on Windows, Mac, Ubuntu.
    • Required: Administrator privileges, OpenJDK (11 or newer), Git Client, Jenkins
  • Install Jenkins as Container:
    • Docker
      • docker pull jenkins/jenkins
      • docker image
      • docker run --detach --publish 8080:8080 --volume jenkins_home:/var/jenkins_home --name jenkins jenkins/jenkins:lts
      • docker exec jenkins cat /var/jenkins_home/secrets/initialAdminPassword //get pass from file for unblock Jenkins
      • open website with localhost:8080 to login and run as on windows or Mac or Ubuntu
  • The Jenkins user interface
  • Install and uninstall plugins
  • Global tool configuration
  • Quiz
    • Question 1 of 7: To install the latest version of Jenkins on a Mac using Homebrew, which command line would you type in the terminal?
      • brew install Jenkins
      • brew services start Jenkins
      • brew reinstall openjdk
      • brew install java
    • Question 2 of 7: Which Docker command connects to the running container and prints the initial admin password for Jenkins?
      • docker exec jenkins cat /var/Jenkins home/secrets/initialAdminPassword (Correct Answer)
      • docker cat /var/jenkins_home/secrets/AdminPassword
      • docker exec jenkins /var/jenkins_home/initialAdminPassword
      • docker exec jenkins cat /var/secrets/AdminPassword
    • Question 3 of 7: If you are making changes at the system level for Jenkins on Ubuntu, you will also need to access your server as the _____ user.
      • regular
      • service
      • local
      • root (Correct Answer)
    • Question 4 of 7: Which menu item on the Jenkins Dashboard will you select to configure tools, their locations, and automatic installers?
      • Manage Jenkins (Correct Answer)
      • People
      • Build History
      • Lockable Resources
    • Question 5 of 7: If you want to uninstall a plugin, which tab would you select under the Manage Plugins menu?
      • Installed (Correct Answer)
      • Available
      • Updates
      • Advanced
    • Question 6 of 7: You are using Jenkins to configure Maven installations. Once you select Add Maven, what must you do next?
      • Give the configuration a name. (Correct Answer)
      • Select the version you want to use.
      • Select the Apply button.
      • Select the Install button.
    • Question 7 of 7: If you are running Jenkins as a Docker Container, what is the minimum RAM you will need?
      • 8 GB
      • 256 MB
      • 100 MB
      • 1 GB (Correct Answer)

2. Jobs in Jenkins

  • Your first Jenkins job
    • Go to Build after create new item.
    • Select "Execute Window Batch Command" for Window or "Execute Shell" for mac or linux
    • type "echo "Hello, Jenkins" " to test this item
    • Apply and Save.
    • Click build now and see the results.
  • Jobtypes: check which type we can use
  • Build description and source code management: we can pull and manage code from git, gitlab or bitbucket
  • Build triggers:
    • Trigger builds remotely (e.g., from scripts): Need create a TOCKEN to do it.
    • Build after other projects are built: we can choose which project will be run before others
    • Build periodically: we can schedule it daily, weekly or monthly...
    • GitHub hook trigger for GITScm polling: Jenkins will run the project based on github activities with complex projects.
    • Poll SCM: should be chosen, it will track the commit activities.
  • The build environment:
    • Delete workspace before build starts
    • Use secret text(s) or file(s).
    • Add timestamps to the Console Output: : Time out when can not receive outputs from the console.
    • Inspect build log for published build scans: Select "Execute Window Batch Command" for Window or "Execute Shell" for mac or linux
    • Terminate a build if it's stuck
    • With Ant: work with Java Ant.
  • Run and monitor jobs
  • Run and monitor jobs using Console output
  • Monitor build trends: Click on "Trend" next to "Build History"; you can see timeline of historical build.
  • Quiz
    • Question 1 of 7: You have created a new item using the Freestyle project type. To save your job configuration and keep working on it, what should you select?
      • OK
      • Save
      • Done
      • Apply(Correct Answer)
    • Question 2 of 7: You need to create a job that requires a series of steps to produce a final outcome. Which type of job is best to select?
      • Pipeline (Correct Answer)
      • Freestyle
      • Multi-configuration
    • Question 3 of 7: Why would you want to discard old builds?
      • to not exceed your allotted amount of builds
      • to erase any duplicate builds
      • to free up space on your server (Correct Answer)
    • Question 4 of 7: You want to trigger a job on a schedule. Which option under the Build Triggers section in Jenkins should you select?
      • Build after other projects are built
      • GitHub hook trigger
      • Trigger builds remotely
      • Build periodically (Correct Answer)
    • Question 5 of 7: Within the build environment section of Jenkins, where can you aggregate downstream test results?
      • under Additional Behaviors
      • under Credentials
      • under Add build step
      • under Post-build Actions (Correct Answer)
    • Question 6 of 7: You have started a job. Under Build History, what does it mean when there is a circle next to the build ID?
      • The job has been paused.
      • The job has not been run before. (Correct Answer)
      • The job has been run before.
      • The job has no data collected.
    • Question 7 of 7: Under Build History, which mark indicates that your job was not successful?
      • a green checkmark
      • a red checkmark
      • a black x
      • a red x (Correct Answer)

3. More detail on jobs

  • Using a global build tool: Note about Git and Maven installation if needed.
  • Source Code Management:
    • add git URL
    • If repository is public, we dont need to add access tocken on "Credentials"
    • Build: Choose correct "Add build step", i.e. Java Maven: Invoke top-level Maven targets is selected.
  • Browse a job's workspace
    • You can see all files and codes here.
    • Wipe Out Current Workspace on the lert to remove all files in the workspace.
  • Manage Artifacts
  • Parameters and environment variables
    • String: example: VERSION_NUMBER
      • We can use: echo $VERSION_NUMBER on linux or echo %VERSION_NUMBER% on window to see it.
    • Choice
      • We can add many options that we want
      • Ex: DEVELOPMENT, STAGING, PRODUCTION.
    • Boolen
      • Similar to choice parameter but it is true or false.
  • Schedule Jobs
    • See it on Build Triggers -> Build periodically
    • Running job automatically
    • Updating sorfware
    • Check any problem with system
    • *****: minute (0-59), hour(0-23), day of month (1-31), month (1-12), Day of week (0-6: Sunday to Saturday)
  • Quiz
    • Question 1 of 6: When adding a string parameter, which three things can you fill in?
      • the default value, the version, and the URL
      • the name, the URL, and the version
      • the name, the default value, and the description (Correct Answer)
      • the version, the command, and the description
    • Question 2 of 6: For choice parameters, if you enter DEVELOPMENT, STAGING, and PRODUCTION, which choice will be used as the default?
      • PRODUCTION
      • DEVELOPMENT (Correct Answer) - first option
      • All three choices will be set as default.
      • STAGING
    • Question 3 of 6: After you name your Boolean parameter, a checkbox parameter will be added to the build interface. If the box is checked, what will the run test environment variable be set to?
      • Active
      • Deployed
      • FALSE
      • TRUE (Correct Answer)
    • Question 4 of 6: Which open-source software must you have in order to use a global build tool in Jenkins?
      • GIT (Correct Answer)
      • Perforce
      • Bitbucket
      • Mercurial
    • Question 5 of 6: Jenkins makes it easy to manage artifacts with which tool?
      • Build Triggers
      • Post-build Actions (Correct Answer)- can clean before building jobs
      • Build Environment
      • Source Code Management
    • Question 6 of 6: To access parameters on a Windows system, which Build command shows the correct syntax?
      • %STRING_PARAMETER% (Correct Answer)
      • $STRING_PARAMETER
      • $STRING_PARAMETER$

4. Organize Jobs with Views and Folders

  • View and folders
  • Create a view: Go to Dashboard to create and setting it.
  • Create a folder: create item as create project but choosing folder.
  • Delete views and folders
  • Quiz
    • Question 1 of 2: You are creating a view and want to include all existing and new jobs with the word BUILD. What is the correct syntax for using a regular expression to include jobs in the view?
    • BUILD_JOBS
    • .BUILD_JOBS.
    • BUILD
    • .BUILD. (Correct Answer)
  • Question 2 of 2: When you delete a folder, what happens to the contents of that folder?
    • The jobs and folders that the folder contains are deleted, but the views remain.
    • All the contents of the folder are deleted, along with the folder. (Correct Answer)
    • The folder itself is saved, but the jobs and views are deleted.
    • The views and folders that the folder contains are deleted, but the jobs remain.

5. Conlcusions

  • Pipeline as code
    • Stored in a file named Jenkinsfile
    • Can be versioned in a code repository
    • Configure Jenkins jobs
    • Contain stages and steps
    • We can define stage with "Build", "Test", ... etc.
    • Steps is in a stage.
    • Chose Job Pipeline when create new item.
    • See Pipeline script and write the Jenkinsfile there.
  • Continuing on with Jenkins
    • Can work with some other software that are similar to Jenkins.
    • Stackoverflow is a good page to discuss jenkins problem.
  • Quiz
    • Question 1 of 1: The following code snippet shows stages of a pipeline. What must each stage also include? pipeline { stages { stage('Build') { } stage('Test') { } } }
      • three steps for each stage
      • a post-build action
      • at least two steps
      • at least one step (Correct Answer)